The invention relates to a medical connector.
In particular, the invention relates to a medical connector which connects two fluid containing elements (in which each fluid containing element can comprise, for example an extracorporeal blood transport tube, an extracorporeal blood treatment device, a medical fluid transport tube, a batch container of medical fluid, etc.), such as to avoid that on coupling at least one or even better neither of the two fluid container elements does not have to rotate upon itself, such as to reduce the risks due to this rotation, such as for example the risk of torsional kinking, or another type of occlusion, in a case in which the fluid container element is a flexible tube. In particular, the medical connector can be a female luer connector.
Specifically, but not exclusively, the invention can be usefully applied to connect an extracorporeal blood circuit (for example a set of fluid transport lines for kidney dialysis, hereinafter referred-to as a “dialysis set”) to an extracorporeal blood treatment (for example a dialyser).
The prior art comprises JP 2004-41612, which describes a female luer connector for connecting a blood transport tube with a male luer port of a dialyser, in which, when the connecter is connected to the dialyser port, a sleeve integrally coupled with the tube is compressed between the connector and the port and thus fixed to the port itself. This solution avoids the tube's being twisted on connection, such as to reduce the risk of kinking (in particular torsional kinking) of the tube.
The prior art further comprises various medical connector each provided with at least two parts of which one is rotatable with respect to the other.
EP 953365 describes a female luer connector having an internal sleeve which bears a truncoconical internal sealing surface with a luer conicity, and an external sleeve which bears an external surface with a screw coupling. The two sleeves are freely rotatable with respect to one another such that a tube, having an end connected to an end of the internal sleeve, is not twisted while the external sleeve is screwed to a male luer. Relative axial displacement between the two sleeves is prevented by a joint formed by an annular radial projection borne by a sleeve inserted in an annular channel afforded in the other sleeve.
EP 775501 describes a female luer having an internal sleeve, made of a relatively soft material, which is twistable with respect to an external sleeve made of a stiffer material. The two sleeves are axially conjoined by means of an annular projection borne by the external sleeve and snap-fitted in an annular channel afforded on the internal sleeve.
EP 1552858 describes a female luer connector having two freely and reciprocally-twistable sleeves and reciprocally constrained in an end of the internal sleeve, and a stopper fixed to the opposite end of the internal sleeve. The external sleeve has a limited freedom of axial movement which is defined by the difference between the axial distance between the flange and the stopper minus the axial length of the external sleeve. When the female luer connector is connected to a male luer connector, the internal sleeve is subjected to extension stress.
JP 2005-329040 describes a female luer connector with an internal sleeve and an external sleeve which are freely twistable with respect to one another in an axial direction due to a projection, borne on one of the two sleeves, which is engaged in a recess afforded in the other. A degree of axial play exists due to the fact that the axial length of the projection is less than the axial length of the recess. The connector of JP 2005-329040 should lead to a lower risk of unexpected disconnection with respect to the connector of EP 1552858.